This invention relates to a machine for pulverizing concrete sheets or slabs, and more particularly to a machine for pulverizing concrete roadbeds having reinforcing steel therein, where the machine is moved along the roadbed during the pulverizing operation.
The replacement of concrete roadways creates a unique and troublesome disposal problem whenever large and bulky concrete slab or sheet structures must be removed from the work site. Such large structures are unsuitable for disposal in landfills unless broken up into small pieces because they tend to create voids underground which prevent adequate filling and compaction. While air and hydraulic hammer machines have been developed to break up such concrete structures into smaller pieces, these machines are particularly unsuitable when the concrete has reinforcing steel embedded therein. Even after hammering, concrete tends to adhere to the steel, resulting in tangled steel and concrete debris which is difficult to move and dispose of. The reinforcing steel itself is usually not reclaimable because of the exceedingly high concrete content which adheres to it. This material is typically trucked to remote disposal sites for inadequate disposition, for no better disposal or recycling program is known for such material. The hauling of this material to remote sites adds to the cost of reconstruction, and the loss of the steel and concrete material for recycling creates a needless economic loss to the owner of the material.
In the reconstruction of roadbeds the old concrete roadbed is typically hammered by means of machines to reduce the size of the concrete and steel fragments to manageable proportions, and these fragments are hauled away. The new roadbed is then filled and graded, and new concrete and reinforcing steel are applied to create a new road. A significant proportion of the total cost of building such a road is attributable to the cost of removing the old roadway, and no significant return is achieved through any recycling process.
U.S. Pat. No. 3,732,023, issued May 8, 1973, discloses a soil stabilization apparatus wherein a machine having a scraper blade cuts beneath an asphalt or asphalt/concrete road by cutting and lifting pieces of the road surface into a pulverizer rotor having cutting and grinding teeth. This apparatus is unsatisfactory for use with concrete roadbeds having reinforced steel imbedded therein, for these roadbeds do not readily break into pieces by lifting, and the reinforcing steel interferes with the operation of the pulverizer rotor.